GOALI: Manufacturing of Two-Dimensional MXene Nanosheets by Salt Solution Etching and Their Solution-based Layer-by-Layer Assembly into Heterostructures

MXenes是一个广泛的二维（2D）陶瓷纳米片家族，具有广泛的组成多样性和可定制性，适用于广泛的实际应用，包括储能，催化，电磁干扰屏蔽，传感器，复合材料和电池。然而，MXene先进制造的挑战阻碍了其广泛的生产和使用。制造挑战包括（i）合成MAX相的困难超过钛铝碳化物，（ii）在合成中使用危险酸，（iii）缺乏化学稳定性，特别是在水性或潮湿环境中，以及（iv）功能膜和涂层中的粘附和控制。这个赠款机会学术联络与产业（GOALI）奖支持基础研究，以提供所需的知识，以满足这些挑战。该项目涉及新的合成和加工途径，使新MXene组合物的可扩展纳米制造成为可能，同时防止降解和功能涂层中MXene控制逐层组装的新方法。一个特别强调的是放在涂层组件功能，如可调光电性能。此外，教育目标包括（1）指导本科生和研究生一起GOALI行业合作伙伴，和（2）通过二维纳米材料为重点的课程增强，联合行业，政府，学术研讨会，和K-12外联参与更广泛的社区.技术方法，以满足与先进制造MXene纳米片的挑战，包括在其合成，蚀刻和组装实验进展.在一个目标中，该项目利用替代蚀刻剂，如熔盐溶液，一步合成下一代MXene，重点是蚀刻剂类型和蚀刻条件如何影响MXene产量，质量和稳定性，以防止化学降解。在另一个目标中，该项目创建包含这些下一代MXene的逐层组装的异质结构功能涂层。这一目标的重点是将MXene的水基溶液组装成独特的异质结构涂层，这些涂层包含具有或不具有聚合物的各种MXene类型的精确堆叠区域。具有聚合物和MXene的交替嵌段的保形涂层的制造允许定制的光电性质，从而导致诸如肖氏结、布拉格反射器和光学滤波器的应用。此外，GOALI项目还与Lynntech合作，在MXene生产和先进制造的可扩展性方面增加专业知识。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

MXenes are a broad family of two-dimensional (2D) ceramic nanosheets with a wide compositional diversity and tailorability of properties for a broad range of practical applications, including energy storage, catalysis, electromagnetic interference shielding, sensors, composites, and batteries. However, challenges in the advanced manufacturing of MXenes prevent widespread production and use. Manufacturing challenges include (i) difficulties in synthesizing MAX phases beyond titanium aluminum carbide, (ii) the use of hazardous acids in the synthesis, (iii) a lack of chemical stability, particularly in aqueous or humid environments, and (iv) adhesion and control in functional films and coatings. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research to provide the knowledge needed to meet these challenges. This project involves new synthesis and processing avenues that enable the scalable nanomanufacturing of new MXene compositions while preventing degradation and new methods of controlled layer-by-layer assembly of MXenes in functional coatings. A special emphasis is placed on coating assembly features such as tunable optoelectronic properties. Additionally, education objectives include (1) mentoring undergraduate and graduate students alongside the GOALI industry partner, and (2) engaging the broader community via 2D nanomaterial-focused curriculum enhancements, a joint industry-government-academic workshop, and K-12 outreach.The technical approach to meeting the challenges with advanced manufacturing of MXene nanosheets includes experimental advances in their synthesis, etching, and assembly. In one objective, this project utilizes alternative etchants such as molten salt solutions for one-step HF-free synthesis of next-generation MXenes with a focus on how etchant type and etching conditions affect MXene yield, quality, and stability against chemical degradation. In another objective, this project creates layer-by-layer-assembled heterostructured functional coatings containing these next-generation MXenes. The focus of this objective is on the water-based solution assembly of MXenes into unique heterostructured coatings that contain precisely stacked regions of various MXene types with or without polymers. The manufacture of conformal coatings with alternating blocks of polymer and MXene allows for tailored optoelectronic properties leading to applications such as Shottky junctions, Bragg reflectors, and optical filters. In addition, this GOALI project has a partnership with Lynntech for added expertise in scalability of MXene production and advanced manufacturing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.